This project can be divided into two sections based on sensors.
1) Ultrasonic Sensor: It is used to calculate the distance between the vehicle and the preceding vehicle. If the distance is smaller than the preset limit it will show a warning in the OLED screen and reduces the speed. If the distance keeps reducing further it stops the vehicle.
2) Accident Detection: Accelerometer sensor is used to monitor the vibrations. If there is an abrupt variation it is considered to be an accident and stops the vehicle. The GPS location is obtained and transmitted to nearby base station which uses NRF24L01 Transceivers.